


A Lasting Promise

by Anonymous



Series: A New Dawn [2]
Category: ARGONAVIS from BanG Dream! AAside (Video Game)
Genre: Alternate Universe - Gender Changes, Multi, Post-Canon, Sickfic, fem!Ren
Language: English
Status: Completed
Published: 2020-10-09
Updated: 2020-10-09
Packaged: 2021-03-08 02:33:45
Rating: General Audiences
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 4,059
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/26918185
Author URL: https://archiveofourown.org/
Summary: Nayuta deals with a sick toddler having a stubborn streak rivaling his own, and to make things worse, his members decide to drop by.Aka the Gyroaxia plus sick child fic
Relationships: Asahi Nayuta/Nanahoshi Ren
Series: A New Dawn [2]
Series URL: https://archiveofourown.org/series/1964038
Kudos: 25
Collections: Anonymous





	A Lasting Promise

**Author's Note:**

> Hey guys! 
> 
> I had this idea going from my last fic. I've introduced some more characters here!
> 
> Also it was definitely just an excuse to write Gyro trying to deal with a toddler because why the hell not!

"That's weird," Reon pointed out when he checked the clock to find that it was past time for practice to begin. "Nayuta's late."

"It is quite unsual," Kenta agreed, pulling out his phone. 

"Oh, I hope nothing's wrong," Miyuki piped up from the back. 

Ryo nodded, echoing the others' worries. 

It was unlike Nayuta to be late for practice, even more for him to miss it. 

Kenta wasted no time in dialing him. "Nayuta?"

"Satozuka?" Nayuta sounded confused on the other end. "Oh right, I forgot to tell you." 

"I just wanted to let you know that practice has begun," Kenta informed. "Unless there's something wrong..."

"I'm not coming today," Nayuta's proclamation surprised the bespectacled man for a moment. "Yukina caught a cold and Ren has an important meeting." 

"Yukina's sick?" Kenta repeated, and the other three immediately look at him, concern in their eyes. 

Nayuta hummed on the other end. "I'd normally just put her to sleep and come, but..." His voice got lower and Kenta could hear the sound of a wailing toddler in the background. 

"If you need any help," Kenta offered. "We can always drop by."

"No!" Nayuta gave his usual response. "Don't even think of coming." 

Kenta opened his mouth to protest but Nayuta cut the call, most likely to deal with his daughter. He let his hand drop to his side, turning to the other three. 

"Is she alright?" Miyuki asked, concern heavy in his voice. It was no secret that despite not having children of their own, the members of Gyroaxia were all incredibly fond of their vocalist's daughter, including Kenta. 

"As you may have heard, Nayuta won't be coming in today because she caught a cold," Kenta dutifully relayed. "And from what I could hear, she's not being very cooperative either for him to leave her with anyone else." 

Reon sighed. "And I expect he told you not to come at any cost?" he guessed. 

Kenta's silence was enough for him. Even after fifteen years, Nayuta had a problem with asking his band for help when he needed it. 

"Well then," Kenta sighed. "Shall we go?" 

"Go where?" Miyuki wondered. 

"To Nayuta's house, of course." 

Reon balked. "Is that a good idea?" he asked. "You know how much he hates us dropping by uninvited, and Ren-san's not there this time to shield us." 

"I want to go help!" Ryo spoke up behind him, scaring the living daylights out of the guitarist. "The little one is unhappy, so it is my duty to help make her happy once more!" 

"Are you serious?" Reon sighed. 

"Now that we're decided," Kenta said, placing his guitar in its case and ignoring Reon's worries as usual. "Let's get going, shall we?" 

* * *

Nayuta loved his daughter, there was no doubt about it. 

She was cute, and she was mostly an easy child, obedient and absolutely eager to please. 

Keyword; _mostly_. 

She also tended to have a stubborn streak that Ren joked she got from him. According to her, it was the same stubborn streak in him that drove him to pursue his music with a one track mind, not letting any obstacles in his path. In her, it was cute when she would struggle to learn the hiragana and not give up even when she'd get it wrong. 

But it certainly wasn't cute when she was down with a cold and a fever, yet refusing sleep because the one she wanted to nurse her back to health wasn't around. 

"Where Mama?!" the toddler cried, attempting to throw off the blankets Nayuta had placed on her. 

Nayuta sighed heavily. "Yukina," he breathed, struggling to keep the annoyance and frustration out of his voice. "I told you before, your mother can't be with you today. I'm here though. Isn't that enough?" 

"Don't want Papa!" the child insisted. "Want Mama!" 

Nayuta gritted his teeth. _Come asking to sleep with me again and we'll have words_ , he thought silently. 

"Well," he tried another tactic. "Mama told me that if you don't behave, she won't come back tonight." 

While he had hoped it would get her to behave, all it ended up doing was making her wail even louder. Nayuta sighed deeply, pinching the bridge of his nose as he mentally ticked off another tactic. He was getting dangerously close to the end of his list. 

At that moment, his doorbell rang, making him look up. It was unusual since he wasn't expecting anyone at this time. 

Quickly instructing Yukina to stay in the bed, he made his way down to the front door, ready to get whatever it was done with so he could get back to his daughter. However his face paled when he opened the door a crack and saw his bandmates standing there with smiles. 

He attempted to close the door once more, but Kenta wedged his foot in the gap, pushing it open and allowing the others in. 

Nayuta ran a hand through his hair. "I thought I told you idiots not to come," he said. 

"Well, we heard Yukina was sick, so of course we needed to come and help!" Miyuki offered, pushing past the vocalist. 

"We brought stuff to help," Reon lifted the two plastic bags in his hand to show them off before placing them on the counter. 

"Get out," Nayuta grumbled. "I don't have the time or energy to deal with you lot."

They ignored him as usual. 

"We got medicine, cold drinks, a book-" Ryo listed out, taking the items out of the bags. "And we got this to wrap around her neck!" He brandished a massive leek. 

"You are _not_ wrapping that around my daughter's neck," Nayuta threatened. 

Before Kenta could ask anything, small steps from behind them caused them to turn. They saw the child in question standing at the bottom of the stairs, rubbing her swollen eyes and sniffling. 

"Yukina?" Nayuta asked, surprise in his voice. 

She said nothing, only falling face first onto the ground. 

"Yukina!" Reon and Miyuki exclaimed, running to her side as Nayuta gave a frustrated exhale. 

"I was worried this would happen," the white haired vocalist murmured. He then walked forward, picking her up, seeing that she was absolutely fine, despite having walked down an entire flight of stairs while being sick. "I thought I told you to stay in bed." 

"Where Mama?" she asked again, pushing her face into the crook of his neck when she saw that there were others there, feeling shy despite being around them since she was born. 

"Are you a broken record?" Nayuta grumbled, feeling the heat of her fever radiating from her forehead. "I told you Mama's not here." 

"Nayuta," he turned to the redhead. "How did this happen?" 

Nayuta sighed. "She went over to play with Goryo's kid yesterday," he explained. "He told me this morning he let them play in the rain." 

"That was dumb, especially with the seasons changing," Reon said, fetching some tissues to help wipe Yukina's runny nose. "Even I know that and I don't even have a kid." 

"I'll definitely kill him for that, just you wait," Nayuta growled, still accepting the tissues Reon offered him. He sighed as the child cried louder. "Give me a minute," he told the waiting four. "I just need to put her to bed." 

Kenta shook his head. "We'll come with you." 

Miyuki solemnly nodded. "We came to help, so let us help."

Nayuta looked like he would normally have complained, but was so far at the end of his patience he didn't have the energy to argue. Instead he offered them a wordless grunt as he took his daughter back up to the bedroom. 

She seemed a bit more obedient, especially seeing that others were here and her natural shyness peeked through, but she still fussed and complained as Nayuta attempted to tuck her back in, leading to him threatening that he would tie her up if need be. That seemed to be the threat that worked, as she allowed him to pull the blankets up to her. 

"Is it serious?" Kenta asked as Nayuta changed the washcloth on the child's forehead. "It's just a cold, isn't it?" 

"Yeah," Nayuta agreed. "But its her fever that concerns me." 

Miyuki pulled the thermometer out of Yukina's mouth then, his eyes widening slightly when he saw the number. "Woah, this is pretty high." 

"Has she taken any medicine?" Reon wondered. 

Nayuta shook his head. "She insists on only taking it from her mother." 

Ryo petted her head. "Cheer up, little one!" he said cheerfully. "Take your medicine, and you'll be happy once more!" 

Yukina shook her head. "Want...Mama..." she said through heavy breaths. 

Ryo looked back up at Nayuta. "Where is her Mama?" 

Nayuta sighed, running a hand down his face. "Weren't you listening?" he growled. "Ren's in a meeting she can't get out of." 

"Gotcha!" Ryo said, turning back down to Yukina. "Will you sleep if I read this to you?" he pulled out a children's book on stars from behind him. 

He looked absolutely crestfallen, however, when Yukina shook her head and repeated her mantra asking for her mother. He looked back at Kenta. 

"Ken-Ken!" Ryo complained, going to his side. "What do I do? I can't make her happy, so I can't pay for my sins!" 

"We're all worried about that," Kenta assured him. He then turned to Nayuta. "Has she eaten anything?" 

Nayuta nodded. "Ren made her some porridge before she left," he replied. "But this fever needs to break, and for that to happen, she needs to sleep." 

"Quite the predicament," Miyuki murmured, his brows furrowed. 

Reon, despite himself, gave a chuckle. This caused Nayuta to turn to him, glaring at him. "Have I said something funny?" he demanded. 

"No, sorry," Reon shook his head. "I just couldn't help myself. It's just...this reminds me of the time Nayuta pushed himself too hard and almost had an attack during a show." He chuckled at the memory. "I remember he still refused to take the inhaler because it ' _fucks with my focus,'_ " he recalled, using air quotes.

Miyuki let himself smile as well. "Ah, I remember that," he grinned. "He was still dating Ren then, wasn't he? How did we convince him to take the inhaler again?"

"We used her as leverage, remember?" Reon continued. "We told him that she was in the audience, and that the inhaler was from her. Only then did he take it." 

"If you two aren't going to be of any help, then get the hell out." 

Kenta had stayed silent throughout the whole thing, tuning out the sounds of his members arguing and the child crying, reading the back of the kids' cold medicine bottle they had bought at the pharmacy before coming over. He then suddenly raised his head, surprising Nayuta, who was the closest to him. 

"Yukina," he said, getting her attention. "We actually met your Mama on our way over." 

"You did?" Yukina asked, her eyes widening and shining. 

"You did?" Nayuta's question was more of suspicion and surprise.

"We did?" Reon murmured. He for certain hadn't gotten the message. 

Kenta nodded. "We did," he continued. "She was the one who gave us this medicine." He held out the bottle in his hand. 

She reached out for it, her tiny hands clasping around it. She considered the bottle for a moment before looking at Nayuta and then Kenta. "Mama...gave medicine?" she asked slowly. 

Kenta hummed softly. "Yes, and you know what she told me?" He continued as the child stared up at him with teary eyes. "She told me that you should take the medicine she gave you, and that you should sleep, because when you wake up, she'll be right here," he gently patted the bed next to her. 

Yukina looked down at his hand and then back up. "Mama...here?" she asked.

Kenta nodded. "But, in order for that, you should take the medicine she gave for you." 

Yukina considered the medicine bottle once more, her little face scrunched in concentration as she weighed her options. If her mother really had sent medicine despite having to go, then perhaps her father was telling the truth when he said she would return. Perhaps her Uncle Kenta would be right, and her mother would be at her side when she would wake up. 

She turned to Kenta, holding out her little finger. "Pinky swear?" 

He let himself smile softly as he wrapped his own little finger around hers, his much larger finger almost the size of her entire hand. "Pinky swear," he repeated. "If I lie, I'll swallow a thousand needles."

Her worries at ease, she turned to her father, holding out the medicine bottle. "Papa, medicine." 

Nayuta held back a snarky comment arising from frustration, just thankful that she was finally being open. "O-of course..." 

All it took was ten minutes for the medicine to begin working, and with the drowsiness accompanied by her father's comforting hand on her head, Yukina was soon off to sleep. 

Nayuta sat back, breathing a sigh of relief. With the worst of it over, he turned to his bandmates. "You guys can go now," he told them. "I'll stay and watch her." 

He was surprised when they shook their heads. "You worked hard today, Nayuta," Reon told him. "You should take a break." He then looked surprised at what he was saying. 

Miyuki nodded. "We'll watch her for you," he said. "I can watch her first." 

"Me second," Ryo put his hand up. "If she wakes up, I'll read to her." He really was wedded to the children's book he had bought. 

Nayuta sighed softly. "I'll leave her in your care then," he managed out. 

Miyuki grinned, but didn't risk teasing the young father further. Instead, he took a seat on the chair beside the child, watching as the rest of his band left the bedroom to go down to the kitchen. 

* * *

Ren sighed as they adjourned for a break, checking her watch to see that they still had a lot of time to spare. 

_Three more hours, huh?_ she thought wryly. 

She was quite antsy. Not only was her daughter sick, but her husband, who had to forgo his precious practice, was caring for her. 

She wondered whether she should call and check in on them, but her decision was put on hold when Yuuto and Wataru made their way to her. She greeted them cheerfully, trying not to let her worry show on her face, but was surprised when Wataru forced Yuuto's head down alongside his own. 

"Apologize, Yu," the redhead commanded. 

"Ren," Yuuto sighed. "I'm sorry I got Yukina sick!" 

"Huh?" Ren asked, quickly shaking her head once it dawned on her. "N-no, it's fine, really!" she insisted. "Nayuta-kun's watching over her." 

"Which I'm sorry for," Yuuto continued. "I swear, I'll be more careful." 

"I'm not angry, Yuuto," she smiled softly. 

"But I am," Wataru stood up, pulling Yuuto up as well. "Excuse me, Ren, while I have a word with my husband." 

Ren watched as Wataru dragged Yuuto away a bit, chewing into him. 

"Seriously, Yu, what were you thinking?" the redhead demanded. "Now Yukina's sick and Akira might be, and you've caused trouble for Ren and Nayuta."

Yuuto sighed. "I know, I'm sorry." 

"Tomorrow, we're going over there first thing in the morning, and you're going to apologize to Nayuta."

"Yes, honey." 

"Oh, and if Akira really does get sick," Wataru prodded his chest with his finger. "You will be the one caring for him. Let's see how you feel about letting kids get wet once you care for a sick toddler." 

"Alright," Yuuto sighed. He leaned forward, taking his husband's hand in his own. "Can you ever forgive me?" he asked, leaning in to speak into his ear. "I swear I'll be more thoughtful with our son, so how can I make it up to you?" 

Wataru looked away, his face reddening a bit. "W-well, as long as you reflect..." 

Ren grinned at that scene, but her smile faltered when she checked her watch once more. 

Two hours and fifty minutes till the meeting ended...

She took a deep breath. _You can get through this, Ren,_ she told herself. _Just a little more time._

* * *

With Miyuki watching Yukina, the other members decided to loiter around the living room. All except Nayuta, who took some extra time to grab a change of shirts, since his old one had a lot of sweat, tears and snot on it. 

He walked back into the living room, pulling the shirt down over his abdomen, noticing that Kenta had taken up residence in the kitchen. He plopped himself down on the couch, as the tiredness and fatigue began to hit him. 

He then felt a familiar scent of coffee in front of him, opening his eyes to see Kenta presenting a cup of coffee with a slice of lemon floating in it. "Here," the elder told him. "It'll help." 

Nayuta accepted the cup with a nod, sipping it and feeling the caffiene almost melt away the exhaustion. Kenta took a seat beside him with a soda can in his hand, throwing the other two drinks as well. 

"Satozuka."

"Hm?"

"You made quite the promise, telling her that her mother would be there when she woke up," Nayuta commented, not moving his eyes from the coffee. "Are you sure you can keep it?" 

Kenta smiled gently at that. "Of course," he said confidently. "The medicine is a stronger one of course." He showed him the label on the bottle. "Says the drowsiness from this lasts six hours at minimum." 

"Six hours?" Nayuta asked. 

"That should be enough time, am I wrong?" 

Nayuta took a deep breath before taking a sip. "It's more than enough," he murmured. 

"I'm actually quite impressed," Reon spoke up from the opposite couch. "Kenta-san, how did you know that would work?" 

"Even my book didn't..." Ryo sadly held the book close beside the guitarist. 

"Was it the story about Nayuta?" Reon continued. "Assumed like father, like daughter?"

"Partly," Kenta said, pushing his glasses up his nose. "But I was also reminded of a similar instance that happened in my own life."

"A similar instance?" Reon asked.

"When my brother and I were kids, my brother caught a cold similarly," Kenta explained. "Our parents were out working that day, so I was stuck looking after him. Just like Yukina, he wanted our mother to nurse him back to health and not me." He chuckled softly at the fond memory. "I had to use a similar tactic to get him to rest too." 

Reon chuckled at that. "I suppose its a common thing with kids, huh?" 

"Well, it happened nearly twenty-five years ago," Kenta brushed it off. "I was more surprised that I remembered it." 

Nayuta then sighed, putting the cup down, tracing the rim of it with his thumb. "I know I said I didn't want you guys to come," he said. "But...you were a big help with Yukina today." He turned his head away. "So...thanks." 

Reon stared at him in shock as Kenta and Ryo smiled gently on the side. "Miyuki's missing this..." Reon murmured. 

"But if you think just because you helped out that I'm going to go easy on you, then you're wrong." 

Despite everything, Reon couldn't help his wide smile. "Yes, yes." 

* * *

Ren practically ran home the second the meeting was over. In fact, she probably would have, had Yuuto not talked her out of it, what with it raining once more, and offered to drive her home instead. It didn't however stop her from insisting he drive at the maximum allowed speed limit so she could get back to her family. 

She was honestly expecting the house to be in shambles by the time she got back, but was surprised at the peace and calm when Nayuta opened the door. 

"How is she?" was the first question Ren asked as her husband let her in. 

While normally he would complain in situations like this, it seemed even he had reached his limit to fight back, instead just helping her get her coat off. "She's fine," he relayed. "She took some medicine and is sleeping now." 

Ren breathed a sigh of relief. "That's great to hear!" she said, walking into the house. However, she paused when she saw the leftover plastic bags on the counter. "Oh, did someone visit?"

Nayuta rubbed the back of his head. "Yeah, my...members visited." 

Over the next ten minutes, as Ren settled back into the house, Nayuta caught her up on everything that had happened, including how Yukina's tantrum had been placated by the promise she and Kenta had made. 

Ren smiled softly. "So that's how it is, huh?" she chuckled. 

"Yeah," Nayuta responded. "It seems stupid, but I didn't really have the energy to say no." 

"It worked, didn't it?" she asked. "And also, it's good that she'll be able to build more trust with Kenta-san." 

"I know," Nayuta replied grumpily. 

"I'll thank them all for helping in the morning," she said, getting up.

He nodded. "You should take a shower," he urged. "It's been a long day for you." 

She agreed with him with a sigh, disappearing for a bit upstairs to take a well earned shower and get ready for bed. Nayuta sat on the couch for a bit longer, going over the events of the day before deciding to go back to the bedroom eventually. 

When he arrived, he found that Ren had finished her shower and had slid into the bed next to her daughter, who was still sleeping peacefully. He went over to the other side, quickly removing the washcloth from her forehead before resting the back of his hand against her skin. 

"Good," he murmured. "Fever broke." 

"That's a relief," Ren smiled. "She'll be okay by the morning then." 

Perhaps it was the sounds of her parents talking, or maybe it was the medicine wearing off, but it was then that Yukina's eyes slowly opened. And the first thing she did was turn to her side, the promise she had made with her uncle still fresh in her mind. 

"Mama...?" she drowsily asked. 

Ren smiled softly, cupping her cheek. "I'm here," she said. "I came just like I said I would." 

Despite being full of sleep, Yukina's eyes still shined as she saw her mother right beside her. "Uncle Kenta...kept promise!" she declared, holding out her little finger.

"He did, yes," Ren met her daughter's enthusiasm. "You were a good girl, I hope. You didn't trouble your father, did you?" 

Yukina promptly shook her head, and Nayuta scoffed slightly on the side. "Yukina was good girl." 

"I see," Ren grinned, ignoring her husband's obvious annoyance. "That's good. Will you continue to be a good girl now and rest? If you rest now, you'll be able to go and play with Akira-kun and the rest of your friends tomorrow." 

The promise of playing with her friends was enough for the child to snuggle back into the blankets, forcing her eyes closed to fall asleep. Nayuta took a deep breath. "I'll go get some water," he informed Ren before making to move. 

However, he was stopped by a gentle tug on his sleeve. 

Turning around, he found his daughter holding onto the sleeve of his shirt, looking at him with big eyes swirling with tears. "Papa...not sleep?" she asked. 

He gritted his teeth. "I'm just getting some water," he said. "I'll be back soon." 

She shook her head. "Papa, sleep," she said, her gaze falling to the ground. 

Nayuta sighed, unable to refuse her. "You want me now, huh?" he grumbled as he slid into the bed. "After rejecting me all day?" 

"Why, Nayuta-kun, are your feelings hurt?" Ren gently teased. 

"Don't even start tonight, Ren. I just want to get to sleep." 

"Alright, alright." 

Yukina, after having confirmed that her mother was right there, then turned to her father, her tiny hands grasping onto his shirt as she fell asleep. 

"Seriously," he grumbled, allowing her to curl into him and sleep. On the other side, Ren placed a soft hand on her stomach, gently petting her to sleep. 

And so, with both her parents at her side, Yukina fell back asleep. 


End file.
